Sealing-strip



UNITED STATES PATENT OFFICE.

FREDERICK W. FARRELL, 0F BROOKFIELD, MASSACHUSETTS, ASSIGNOR 'I'O WILLIAM I MACLAURIN, OF BROOKFIELD, MASSACHUSETTS.

SEALING-STRIP.

No Drawing.

T 0 all whom it may concern Be it known that I, FREDERICK WV. F AR- BELL, a citizen of the'United States, residjects of the invention to provide said strip,

tape or member with an adhesive material which avoids the objections to the sealing tapes or members heretofore used.

It is well known that in the art of packaging, articles and material by the use of cartons or containers made of fiber. board or somewhat similar manufactured board it is the custom to secure the closure flaps or parts of said cartonsor containers by means of strips of paper adhesively secured in place to bindor bridge edges of said flaps or parts whereby to secure said flaps or parts to one another or to some adjacent part of the carton or container. One method of securing said strips of paper or tapes has been: to coat the same with glue which became hard and non stic'ky or non-tacky when dry whereby the coated strips or 'tapcs could be rolled into rolls convenient for transportation and for handling by machines in the course of their application to the cartons or containers. Usually, as a step immediately preceding the application of these strips or tapes, it has been customary to pass such strips or tapes through moistening devices to supply moisture to the glue or render the same tacky or capable of adhering to the surface to which the strip was applied.

In the course of procedure just above briefly described it has been found diflicult ture unduly dissolves the glue which mili- Specification of Letters Patent.

Patented NOV. 16, 1920.

Application filed December 22, 1916. Serial No. 138,471.

tates against its adhesion. It is also found that said glue is unduly expensive.

The purpose of the present invention in its more specific aspect is to provide a tape, strip, member or material having a coating of an adhesive material which can be rendered tacky without the application thereto of moisture whereby injury to the machinery is avoided and the affixing of the tape, strip. member or material to the carton or container is rendered more positive. The alternative to the use of moisture or liquid of some kind to render the adhesive of said tape, strip, etc., tacky is the use of an adhesive which, normally non-taclny, becomes tacky under a suitable increase in temperature.

The use of rubber, tta percha, gums and other somewhat similar materials for this purpose is at present inexpedient because of their cost.

After considerable experimentation with materials of a nature to become or to remain tacky without the use of moisture I find that Trinidad asphalt is well suited' for the purpose and when applied as a thin coating to a strip or sheet of paper can be utilized as an extremelv strong adhesive to secure said strip or sheet of paper to another paper' article particularly when the adhesion of said'parts is effected under heat and pressure. Ifiud further however that such asphalt after its application to the strip, tape or member will not harden but will remain somewhat tacky whereby the handling of said strip, tape, etc., is so difficult as to be almost impracticable and the rolling of said sealing strip, tape, etc., will not be practical because the asphaltic coating will adhere to the clean surface of said strip in the winding and prevent unwinding of the same. I am of course aware of the use of various non-adhesive coatings of loose material supout unduly adhering to parts coming in contact therewith while under an abnormal temfrom in a mixture of six or seven parts of 'clay to ten parts of asphalt. The adhesive thus produced is applied as a very thin coating to a base of paper or other fabric or material and some portion of said coating may partially enter and unite with the surface structure of said base paper, fabric or material Without saturating the same as the back of said base should be clean and free from adhesive. Usually said adhesive is applied to comparatively wide strips or webs of the paper, fabric or material which latter is then preferably cut into narrow strips or tapes adapted for economical and convenient use. When said adhesive coating becomesdry the strips or tapes may be wound into rolls without the layers thereof sticking together.

In some cases when a comparatively small proportion of clay is used or when the asphalt is unduly tacky I find that it is desirable to reduce the tackiness of the surface of the-adhesive after its application to the paper. When this latter course is desirable or necessary I prefer to apply to the surface of the adhesive a quantity of clay or similar inert mineral matter and apply a slight friction or rubbing thereto whereby the fine particles of said clay become mechanically incorporated with or received by the asphaltic surface of the adhesive and the superficial tackiness of said surface is reduced or neutralized without materially reducing the adhesive quality of the coating when subjected to a suitable heat.

The improved sealing tapes or strips are used by placing the same with the coated surface in contact with the surface to which said'strip or tape is to be affixed and applying heat and. pressure to the back or uncoated surface of the strip or tape. This heat and pressure need not be applied simultaneously as the tape or strip may be subjected to: heat to render the adhesivetacky or semi-fluid slightly prior to the placing of adhesive into the surface .structure of the article to which said tape or strip has been thus applied.

As the improved adhesive is not materially affected by moisture in the atmosphere its adhesive binding qualities remain practically permanent after application.

In addition to its use as a sealing tape or strip to seal or secure two adjacent flaps or parts of a carton, container or wrapper, said adhesive strips or members may be used as corner stays for boxes or other stays or reinforcing members. Said adhesive strips may be used to secure together or bridge the adjacent edges of two pieces of veneer or of any other members or articles. I

It is to be understood that the inert material used to neutralize or load the asphalt should be ofsuch extremefineness as to its particles that said particles neither individually nor collectively will prevent any material area or quality of the asphalt from reaching the surface to which said asphalt is intended to adhere when said asphaltis subjected to a suitable temperature. I do not therefore intend to claim herein, as such inert material, the use of sand, powdered soapstone or other flaky mineral substance.

Having thus described my invention I claim as new and desire to secure by Letters Patent: e

1. A sealing strip of the character described, comprising a strip of'paper and a coating of asphaltum on said paper, said coating containing a suflicient proportion of pulverized mineral matter to render the asphaltum non-adhesive at normal temperatures but enabling the coating to become adhesive upon the application of heat thereto.

2. A sealing strip of the character described, comprising a strip ofpaper, a coat ing on said strip of asphaltum and pulverized mineral matter, the exposed surface of said coating having pulverized mineral matter, rubbed thereinto to render the surface of said coating non-adhesive at normal temperatures, but permitting said coating to become adhesive upon the application of heat thereto. 

